There is known an engine which is provided with an exhaust-driven supercharger such as a turbocharger or the like and an electrically-driven supercharger (for example, refer to a Patent literature 1). There is also known an exhaust-driven supercharger having some type of an adjusting mechanism such as, for example, a variable nozzle (VN: Variable Nozzle Mechanism) and a waste gate valve (WGV) which is configured to be capable of changing a supercharging efficiency according to an opening/closing state thereof.